One of the projects I'm working on has become unlodable.
When I try to load it Reaper just closes.
Same problem with loading backups of the same project.
I have been working on this for months, and it was nearly finished, any ideals?
Imac 27 running 10.15.1

I can't find the recovery mode anymore to open a project without fx.
There's no check boxes in the "open project" window. Only the Open/cancel buttons
Is there a new way to do it in Reaper 6 ?

I have Reaper 6.02 on MacOS Catalina 10.15.2

Not sure if this might perhaps be a bug (on Catalina), but it's probably worth posting this into the Bug Report section, as well: https://forum.cockos.com/forumdisplay.php?f=22
The additional checkbox options in the 'open project' window still show up fine here on 6.02 (using on an older macOS version 10.10.5).

I guess you already tried if resizing the 'open project' window makes any difference.
But another option you can try for loading projects with FX offline is holding CMD + SHIFT while loading a project (via the open project window).

And just in case: did you install Reaper using the 'OS X 10.15 Catalina' installer (which is a separate one besides the 'OS X 64-bit' one for older macOS versions 10.5-10.14)?